DNS: mark Quad9 as Switzerland based (#2214)

Resolves: #2212

https://quad9.net/news/blog/quad9-public-domain-name-service-moves-to-switzerland-for-maximum-internet-privacy-protection/

Author: Mikaela

_includes/sections/dns.html

@@ -415,8 +415,8 @@ <h1 id="dns" class="anchor">
         </td>
         <td>Anycast (based in
           <span class="no-text-wrap">
-            <span class="flag-icon flag-icon-us"></span>
-            US)
+            <span class="flag-icon flag-icon-ch"></span>
+            Switzerland)
           </span>
         </td>
         <td>